Examining which factors influence age of onset in males and females with schizophrenia

The relationship between sex and functional outcome in first-episode schizophrenia: the role of premorbid adjustment and insight

BACKGROUND

Studies that examined sex differences in first-episode patients consistently show that males compared to females have poor premorbid adjustment, earlier age of onset, worse clinical characteristics, and poorer outcomes. However, little is known about potential mediators that could explain these sex differences.

METHODS

Our sample consisted of 137 individuals with first episode schizophrenia (males, n = 105; 77%) with a mean age of 22.1(s.d. = 4.1) years and mean education of 12.5(s.d. = 1.7) years. At entry, patients were within 2 years of their first psychotic episode onset. Baseline assessments were conducted for premorbid adjustment, symptoms, cognitive functioning, insight, and at 6-months for role and social functioning.

RESULTS

Males as compared to females had poorer premorbid adjustment across several key developmental periods (p < 0.01), an earlier age of onset [M = 20.3(3.3) v. 22.8(5.6), p = 0.002], more negative symptoms (p = 0.044), poorer insight (p = 0.031), and poorer baseline and 6-month role (p = 0.002) and social functioning (p = 0.034). Several of these variables in which males showed impairment were significant predictors of 6-month role and social functioning. Premorbid adjustment and insight mediated the relationship between sex and role and social functioning at 6-months, but not negative symptoms.

DISCUSSION

Males compared to females were at lower levels across several key premorbid and clinical domains which are strongly associated with functional outcome supporting the hypothesis that males might have a more disabling form of schizophrenia. The relationship between sex with role and social functioning was mediated through premorbid adjustment and insight suggesting pathways for understanding why females might have a less disabling form of schizophrenia.

The global burden of schizophrenia and the impact of urbanization during 1990-2019: An analysis of the global burden of disease study 2019

BACKGROUND AND HYPOTHESIS

The burden of schizophrenia is increasing. Assessing the global distribution of schizophrenia and understanding the association between urbanization factors and schizophrenia are crucial.

STUDY DESIGN

We conducted a two-stage analysis utilizing public data from GBD (global burden of disease) 2019 and the World Bank. First, the distribution of schizophrenia burden at the global, regional, and national levels as well as temporal trends was analyzed. Then, four composite indicators of urbanization (including demographic, spatial, economic, and eco-environment urbanization) were constructed from ten basic indicators. Panel data models were used to explore the relationship between urbanization indicators and the burden of schizophrenia.

RESULTS

In 2019, there were 23.6 million people with schizophrenia, an increase of 65.85% from 1990, and the country with the largest ASDR (age-standardized disability adjusted life years rate) was the United States of America, followed by Australia, and New Zealand. Globally, the ASDR of schizophrenia rose with the sociodemographic index (SDI). In addition, six basic urbanization indicators including urban population proportion, employment in industry/services proportion, urban population density, the population proportion in the largest city, GDP, and PM_2.5 concentration were positively associated with ASDR of schizophrenia, with the largest coefficients being urban population density. Overall, demographic, spatial, economic, and eco-environment urbanization all had positive effects on schizophrenia, and the estimated coefficients indicated that demographic urbanization was the most significant influence.

CONCLUSIONS

This study provided a comprehensive description of the global burden of schizophrenia and explored urbanization as a factor contributing to the variation in the burden of schizophrenia, and highlighted policy priorities for schizophrenia prevention in the context of urbanization.

Environmental Risk Factors and Cognitive Outcomes in Psychosis: Pre-, Perinatal, and Early Life Adversity

Risk for psychosis begins to accumulate as early as the fetal period through exposure to obstetric complications like fetal hypoxia, maternal stress, and prenatal infection. Stressors in the postnatal period, such as childhood trauma, peer victimization, and neighborhood-level adversity, further increase susceptibility for psychosis. Cognitive difficulties are among the first symptoms to emerge in individuals who go on to develop a psychotic disorder. We review the relationship between pre-, perinatal, and early childhood adversities and cognitive outcomes in individuals with psychosis. Current evidence shows that the aforementioned environmental risk factors may be linked to lower overall intelligence and executive dysfunction, beginning in the premorbid period and persisting into adulthood in individuals with psychosis. It is likely that early life stress contributes to cognitive difficulties in psychosis through dysregulation of the body's response to stress, causing changes such as increased cortisol levels and chronic immune activation, which can negatively impact neurodevelopment. Intersectional aspects of identity (e.g., sex/gender, race/ethnicity), as well as gene-environment interactions, likely inform the developmental cascade to cognitive difficulties throughout the course of psychotic disorders and are reviewed below. Prospective studies of birth cohorts will serve to further clarify the relationship between early-life environmental risk factors and cognitive outcomes in the developmental course of psychotic disorders. Specific methodological recommendations are provided for future research.

Age of onset by sex in schizophrenia: Proximal and distal characteristics

BACKGROUND

Earlier schizophrenia onset in men relative to women has been a consistent finding in the literature, but a nuanced understanding of underlying reasons remains elusive. Further consideration should be given to factors associated with sex differences in age of onset.

METHOD

Participants with schizophrenia were derived from the 2010 Australian Survey of High Impact Psychosis (n = 857). The SHIP survey constituted a representative, population-based study of almost 1.5 million Australian adults seen at various mental health services, and assessed personal health information, psychiatric comorbidities as well as psychosis illness and treatment. Hierarchical clustering was employed to identify age of onset by sex. Within-sex comparisons on distal and proximal factors affecting age of onset were conducted.

RESULTS

Using modal age, two and three clusters were respectively found in men (early versus late onset) and women (early versus mid versus late onset). Early onset groups in both sexes had an increased family history of psychosis compared to older onset, but other risk factors were not consistent across the sexes. Less premorbid impairment was noted in females with middle to later onset schizophrenia.

CONCLUSION

These findings further inform our understanding of the pathogenesis of schizophrenia. Added explorations of trends in older onset schizophrenia cohorts is especially important.

The mediating effect of brain-derived neurotrophic factor levels on childhood trauma and psychiatric symptoms in patients with first-episode schizophrenia

BACKGROUND

Previous studies have implicated childhood trauma and abnormal brain-derived neurotrophic factor in the pathogenesis of schizophrenia. Here, we explored whether brain-derived neurotrophic factor levels mediated the relationship between childhood trauma and psychopathological symptoms in patients with first-episode schizophrenia.

METHODS

Patients with first-episode schizophrenia (n = 192) and healthy controls (n = 136) were enrolled. Childhood traumatic experiences and psychopathology were assessed by Childhood Trauma Questionnaire and Positive and Negative Syndrome Scale, respectively. Enzyme-linked immunosorbent assay was used to quantify brain-derived neurotrophic factor levels.

RESULTS

The patients with first-episode schizophrenia experienced more severe childhood trauma and had lower serum brain-derived neurotrophic factor levels than healthy controls. Emotional abuse and Childhood Trauma Questionnaire total score showed positive correlation with Positive and Negative Syndrome Scale positive, general psychopathological subscore and total score. Emotional neglect showed positive correlation with Positive and Negative Syndrome Scale positive subscore. Physical neglect was positively associated with Positive and Negative Syndrome Scale negative subscore. Emotional neglect and Childhood Trauma Questionnaire total score were negatively correlated with serum brain-derived neurotrophic factor levels. The serum brain-derived neurotrophic factor levels mediated the relationship between both Childhood Trauma Questionnaire total score and Positive and Negative Syndrome Scale total score and negative symptoms in the patients. The brain-derived neurotrophic factor levels also mediated the relationship between emotional neglect and Positive and Negative Syndrome Scale total score in the patients.

CONCLUSION

Childhood trauma might contribute to the clinical symptoms of schizophrenia by affecting brain-derived neurotrophic factor levels. Perhaps we can prevent schizophrenia by reducing childhood traumatic experiences.

No influence of sex on the relationship between schizotypy factors and executive control across the schizophrenia spectrum

Sex differences in symptoms and executive control across schizophrenia spectrum disorders (SSD) are consistently reported. Similarly, these findings of sex differences are also observed in schizotypy, that is, schizophrenia-like features occurring in healthy individuals in the absence of a clinical diagnosis. This study aimed to examine the relationships between performance on three major domains of executive control: performance monitoring, response inhibition, and cognitive set-shifting, and schizotypy factor scores in both SSD patients and healthy controls (HCs), and whether sex moderated any relationships observed. A total of 111 (67 males and 44 females) patients with SSD and 258 (129 males and 129 females) HCs were included in this study. Schizotypal personality traits (in both SSD and HC) was assessed using the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE). Executive control performance was assessed using seven tasks. Stepwise linear regressions revealed that performance on cognitive set-shifting tasks was significantly associated with the introvertive anhedonia, cognitive disorganisation, and unusual experiences subscales of the O-LIFE. When sex was examined as a moderator, it was not a significant moderator of any of the relationships between cognitive set-shifting tasks and schizotypy factors. The results suggest that independent of sex, cognitive set-shifting ability is associated to an increased vulnerability to schizotypal personality traits, although performance monitoring and response inhibition did not.

Risk of First-Episode Schizophrenia in Aged Adults Increased During COVID-19 Outbreak

We noticed an unusual increase of aged adults in first-episode schizophrenia in January and February 2020 since the outbreak of COVID-19. This retrospective study aims to statistically validate this observation and find potential risk factors, if applicable. The demographics of schizophrenia in outpatients (both first-episode and follow-up) from January to March 2020 (36,624 records) and similar periods of 2017-2019 (114,141 records) were analyzed and compared to minimize seasonal influence. Limited personal information (age, gender, approximate residence) was investigated to find risk factors. After considering seasonal factors such as the Spring festival, the age of the first-episode schizophrenia was significantly increased in January (46.60 ± 15.14) and February (51.53 ± 14.74) but went back to normal in March 2020 (38.89 ± 14.59), compared with similar periods from 2017 to 2019 (Jan., 40.77 ± 15.26; Feb., 39.69 ± 15.10; Mar., 42.04 ± 15.83). Meanwhile, a slight but not significant change was found in the distribution of gender and approximate residence (urban/suburb). Our data supported that risk of first-episode schizophrenia in aged adults increased during the COVID-19 outbreak, which is consistent with the fact that COVID-19 is more lethal to elders. Public healthcare should prepare in advance for potential risks in public mental health, especially for elders.

Cognitive heterogeneity in first-episode psychosis and its relationship with premorbid developmental adjustment

BACKGROUND

Patients with schizophrenia spectrum disorders have been increasingly recognised to form cognitive subgroups with differential levels of impairment. Using cluster analytical techniques, this study sought to identify cognitive clusters in a sample of first-episode psychosis (FEP) patients and examine clinical and developmental differences across the resultant groups.

METHODS

In total, 105 FEP patients in the University of California Los Angeles Aftercare Research Program were assessed for cognition, symptoms and premorbid developmental adjustment. Hierarchical cluster analysis with Ward's method and squared Euclidean distance was conducted, confirmed by discriminant function analysis and optimised with k-means clustering. The stability of the solution was evaluated through split-sample (random, 80 and 70% samples) and alternate method (average linkage method) replication via Cohen's κ analysis. Controlling for multiple comparisons, one-way analysis of variances examined group differences in symptom severity and premorbid adjustment.

RESULTS

Three groups were identified: severely impaired (n = 27), moderately impaired (n = 41) and relatively intact (n = 37). There were no significant differences in symptom severity across the groups. Significant differences were observed for scholastic performance at three different developmental stages: childhood, early adolescence and late adolescence, with the relatively intact group demonstrating significantly better scholastic performance at all three stages than both the moderately impaired and severely impaired groups (who did not significantly differ from each other).

CONCLUSIONS

The findings add to growing evidence that cognitive clusters in FEP mirror that of later-stage schizophrenia. They also suggest that premorbid scholastic performance may not just be a risk factor for developing schizophrenia, but is also related to cognitive impairment severity and potentially to prognosis.

Gender Differences in Clinical and Psychosocial Features Among Persons With Schizophrenia: A Mini Review

An extensive literature regarding gender differences relevant to several aspects of schizophrenia is nowadays available. It includes some robust findings as well as some inconsistencies. In the present review, we summarize the literature on gender differences in schizophrenia relevant to clinical and social outcome as well as their determinants, focusing on clinical variables, while gender differences on biological factors which may have an impact on the outcome of the disorder were not included herewith. Consistent findings include, in male with respect to female patients, an earlier age of illness onset limited to early- and middle-onset schizophrenia, a worse premorbid functioning, a greater severity of negative symptoms, a lower severity of affective symptoms and a higher rate of comorbid alcohol/substance abuse. Discrepant findings have been reported on gender differences in positive symptoms and in social and non-social cognition, as well as in functional outcome and rates of recovery. In fact, despite the overall finding of a more severe clinical picture in males, this does not seem to translate into a worse outcome. From the recent literature emerges that, although some findings on gender differences in schizophrenia are consistent, there are still aspects of clinical and functional outcome which need clarification by means of further studies taking into account several methodological issues.

Ketamine Alters Functional Gamma and Theta Resting-State Connectivity in Healthy Humans: Implications for Schizophrenia Treatment Targeting the Glutamate System

Disturbed functional connectivity is assumed to cause neurocognitive deficits in patients suffering from schizophrenia. A Glutamate N-methyl-D-aspartate receptor (NMDAR) dysfunction has been suggested as a possible mechanism underlying altered connectivity in schizophrenia, especially in the gamma- and theta-frequency range. The present study aimed to investigate the effects of the NMDAR-antagonist ketamine on resting-state power, functional connectivity, and schizophrenia-like psychopathological changes in healthy volunteers. In a placebo-controlled crossover design, 25 healthy subjects were recorded using resting-state 64-channel-electroencephalography (EEG) (eyes closed). The imaginary coherence-based Multivariate Interaction Measure (MIM) was used to measure gamma and theta connectivity across 80 cortical regions. The network-based statistic was applied to identify involved networks under ketamine. Psychopathology was assessed with the Positive and Negative Syndrome Scale (PANSS) and the 5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC). Ketamine caused an increase in all PANSS (p < 0.001) as well as 5D-ASC scores (p < 0.01). Significant increases in resting-state gamma and theta power were observed under ketamine compared to placebo (p < 0.05). The source-space analysis revealed two distinct networks with an increased mean functional gamma- or theta-band connectivity during the ketamine session. The gamma-network consisted of midline regions, the cuneus, the precuneus, and the bilateral posterior cingulate cortices, while the theta-band network involved the Heschl gyrus, midline regions, the insula, and the middle cingulate cortex. The current source density (CSD) within the gamma-band correlated negatively with the PANSS negative symptom score, and the activity within the gamma-band network correlated negatively with the subjective changed meaning of percepts subscale of the 5D-ASC. These results are in line with resting-state patterns seen in people who have schizophrenia and argue for a crucial role of the glutamate system in mediating dysfunctional gamma- and theta-band-connectivity in schizophrenia. Resting-state networks could serve as biomarkers for the response to glutamatergic drugs or drug development efforts within the glutamate system.

Schizophrenia Psychosis in Women

A first step towards personalized medicine is to consider whether, for some disorders, the safest and most effective treatment of women needs to differ from standard guideline recommendations developed on the basis of clinical trials conducted, for the most part, in men. A second step is to consider how women’s reproductive stages—pre-pubertal years, menstrual phases, pregnancy trimesters, lactation and postpartum periods, menopausal and postmenopausal/aging status—affect the optimal choice of treatment. This review focuses on these two steps in the treatment of psychosis, specifically schizophrenia. It discusses genetics, precursors and symptoms of schizophrenia, reproductive and associated ethical issues, antipsychotic drug response and adverse effects, substance abuse, victimization and perpetration of violence, and issues of immigration and of co-morbidity. The conclusions, while often based on clinical experience and theoretical considerations rather than strictly on the evidence of randomized controlled trials, are that clinical recommendations need to consider clinical and role differences that exist between men and women and make appropriate correction for age and reproductive status.